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TOMOYO Linux Cross Reference
Linux/include/linux/slab.h

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 /*
  3  * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
  4  *
  5  * (C) SGI 2006, Christoph Lameter
  6  *      Cleaned up and restructured to ease the addition of alternative
  7  *      implementations of SLAB allocators.
  8  * (C) Linux Foundation 2008-2013
  9  *      Unified interface for all slab allocators
 10  */
 11 
 12 #ifndef _LINUX_SLAB_H
 13 #define _LINUX_SLAB_H
 14 
 15 #include <linux/gfp.h>
 16 #include <linux/overflow.h>
 17 #include <linux/types.h>
 18 #include <linux/workqueue.h>
 19 #include <linux/percpu-refcount.h>
 20 
 21 
 22 /*
 23  * Flags to pass to kmem_cache_create().
 24  * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set.
 25  */
 26 /* DEBUG: Perform (expensive) checks on alloc/free */
 27 #define SLAB_CONSISTENCY_CHECKS ((slab_flags_t __force)0x00000100U)
 28 /* DEBUG: Red zone objs in a cache */
 29 #define SLAB_RED_ZONE           ((slab_flags_t __force)0x00000400U)
 30 /* DEBUG: Poison objects */
 31 #define SLAB_POISON             ((slab_flags_t __force)0x00000800U)
 32 /* Align objs on cache lines */
 33 #define SLAB_HWCACHE_ALIGN      ((slab_flags_t __force)0x00002000U)
 34 /* Use GFP_DMA memory */
 35 #define SLAB_CACHE_DMA          ((slab_flags_t __force)0x00004000U)
 36 /* Use GFP_DMA32 memory */
 37 #define SLAB_CACHE_DMA32        ((slab_flags_t __force)0x00008000U)
 38 /* DEBUG: Store the last owner for bug hunting */
 39 #define SLAB_STORE_USER         ((slab_flags_t __force)0x00010000U)
 40 /* Panic if kmem_cache_create() fails */
 41 #define SLAB_PANIC              ((slab_flags_t __force)0x00040000U)
 42 /*
 43  * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
 44  *
 45  * This delays freeing the SLAB page by a grace period, it does _NOT_
 46  * delay object freeing. This means that if you do kmem_cache_free()
 47  * that memory location is free to be reused at any time. Thus it may
 48  * be possible to see another object there in the same RCU grace period.
 49  *
 50  * This feature only ensures the memory location backing the object
 51  * stays valid, the trick to using this is relying on an independent
 52  * object validation pass. Something like:
 53  *
 54  *  rcu_read_lock()
 55  * again:
 56  *  obj = lockless_lookup(key);
 57  *  if (obj) {
 58  *    if (!try_get_ref(obj)) // might fail for free objects
 59  *      goto again;
 60  *
 61  *    if (obj->key != key) { // not the object we expected
 62  *      put_ref(obj);
 63  *      goto again;
 64  *    }
 65  *  }
 66  *  rcu_read_unlock();
 67  *
 68  * This is useful if we need to approach a kernel structure obliquely,
 69  * from its address obtained without the usual locking. We can lock
 70  * the structure to stabilize it and check it's still at the given address,
 71  * only if we can be sure that the memory has not been meanwhile reused
 72  * for some other kind of object (which our subsystem's lock might corrupt).
 73  *
 74  * rcu_read_lock before reading the address, then rcu_read_unlock after
 75  * taking the spinlock within the structure expected at that address.
 76  *
 77  * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
 78  */
 79 /* Defer freeing slabs to RCU */
 80 #define SLAB_TYPESAFE_BY_RCU    ((slab_flags_t __force)0x00080000U)
 81 /* Spread some memory over cpuset */
 82 #define SLAB_MEM_SPREAD         ((slab_flags_t __force)0x00100000U)
 83 /* Trace allocations and frees */
 84 #define SLAB_TRACE              ((slab_flags_t __force)0x00200000U)
 85 
 86 /* Flag to prevent checks on free */
 87 #ifdef CONFIG_DEBUG_OBJECTS
 88 # define SLAB_DEBUG_OBJECTS     ((slab_flags_t __force)0x00400000U)
 89 #else
 90 # define SLAB_DEBUG_OBJECTS     0
 91 #endif
 92 
 93 /* Avoid kmemleak tracing */
 94 #define SLAB_NOLEAKTRACE        ((slab_flags_t __force)0x00800000U)
 95 
 96 /* Fault injection mark */
 97 #ifdef CONFIG_FAILSLAB
 98 # define SLAB_FAILSLAB          ((slab_flags_t __force)0x02000000U)
 99 #else
100 # define SLAB_FAILSLAB          0
101 #endif
102 /* Account to memcg */
103 #ifdef CONFIG_MEMCG_KMEM
104 # define SLAB_ACCOUNT           ((slab_flags_t __force)0x04000000U)
105 #else
106 # define SLAB_ACCOUNT           0
107 #endif
108 
109 #ifdef CONFIG_KASAN
110 #define SLAB_KASAN              ((slab_flags_t __force)0x08000000U)
111 #else
112 #define SLAB_KASAN              0
113 #endif
114 
115 /* The following flags affect the page allocator grouping pages by mobility */
116 /* Objects are reclaimable */
117 #define SLAB_RECLAIM_ACCOUNT    ((slab_flags_t __force)0x00020000U)
118 #define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
119 
120 /* Slab deactivation flag */
121 #define SLAB_DEACTIVATED        ((slab_flags_t __force)0x10000000U)
122 
123 /*
124  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
125  *
126  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
127  *
128  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
129  * Both make kfree a no-op.
130  */
131 #define ZERO_SIZE_PTR ((void *)16)
132 
133 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
134                                 (unsigned long)ZERO_SIZE_PTR)
135 
136 #include <linux/kasan.h>
137 
138 struct mem_cgroup;
139 /*
140  * struct kmem_cache related prototypes
141  */
142 void __init kmem_cache_init(void);
143 bool slab_is_available(void);
144 
145 extern bool usercopy_fallback;
146 
147 struct kmem_cache *kmem_cache_create(const char *name, unsigned int size,
148                         unsigned int align, slab_flags_t flags,
149                         void (*ctor)(void *));
150 struct kmem_cache *kmem_cache_create_usercopy(const char *name,
151                         unsigned int size, unsigned int align,
152                         slab_flags_t flags,
153                         unsigned int useroffset, unsigned int usersize,
154                         void (*ctor)(void *));
155 void kmem_cache_destroy(struct kmem_cache *);
156 int kmem_cache_shrink(struct kmem_cache *);
157 
158 /*
159  * Please use this macro to create slab caches. Simply specify the
160  * name of the structure and maybe some flags that are listed above.
161  *
162  * The alignment of the struct determines object alignment. If you
163  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
164  * then the objects will be properly aligned in SMP configurations.
165  */
166 #define KMEM_CACHE(__struct, __flags)                                   \
167                 kmem_cache_create(#__struct, sizeof(struct __struct),   \
168                         __alignof__(struct __struct), (__flags), NULL)
169 
170 /*
171  * To whitelist a single field for copying to/from usercopy, use this
172  * macro instead for KMEM_CACHE() above.
173  */
174 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field)                 \
175                 kmem_cache_create_usercopy(#__struct,                   \
176                         sizeof(struct __struct),                        \
177                         __alignof__(struct __struct), (__flags),        \
178                         offsetof(struct __struct, __field),             \
179                         sizeof_field(struct __struct, __field), NULL)
180 
181 /*
182  * Common kmalloc functions provided by all allocators
183  */
184 void * __must_check krealloc(const void *, size_t, gfp_t);
185 void kfree(const void *);
186 void kfree_sensitive(const void *);
187 size_t __ksize(const void *);
188 size_t ksize(const void *);
189 
190 #define kzfree(x)       kfree_sensitive(x)      /* For backward compatibility */
191 
192 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
193 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
194                         bool to_user);
195 #else
196 static inline void __check_heap_object(const void *ptr, unsigned long n,
197                                        struct page *page, bool to_user) { }
198 #endif
199 
200 /*
201  * Some archs want to perform DMA into kmalloc caches and need a guaranteed
202  * alignment larger than the alignment of a 64-bit integer.
203  * Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
204  */
205 #if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
206 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
207 #define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
208 #define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
209 #else
210 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
211 #endif
212 
213 /*
214  * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
215  * Intended for arches that get misalignment faults even for 64 bit integer
216  * aligned buffers.
217  */
218 #ifndef ARCH_SLAB_MINALIGN
219 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
220 #endif
221 
222 /*
223  * kmalloc and friends return ARCH_KMALLOC_MINALIGN aligned
224  * pointers. kmem_cache_alloc and friends return ARCH_SLAB_MINALIGN
225  * aligned pointers.
226  */
227 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN)
228 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN)
229 #define __assume_page_alignment __assume_aligned(PAGE_SIZE)
230 
231 /*
232  * Kmalloc array related definitions
233  */
234 
235 #ifdef CONFIG_SLAB
236 /*
237  * The largest kmalloc size supported by the SLAB allocators is
238  * 32 megabyte (2^25) or the maximum allocatable page order if that is
239  * less than 32 MB.
240  *
241  * WARNING: Its not easy to increase this value since the allocators have
242  * to do various tricks to work around compiler limitations in order to
243  * ensure proper constant folding.
244  */
245 #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
246                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
247 #define KMALLOC_SHIFT_MAX       KMALLOC_SHIFT_HIGH
248 #ifndef KMALLOC_SHIFT_LOW
249 #define KMALLOC_SHIFT_LOW       5
250 #endif
251 #endif
252 
253 #ifdef CONFIG_SLUB
254 /*
255  * SLUB directly allocates requests fitting in to an order-1 page
256  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
257  */
258 #define KMALLOC_SHIFT_HIGH      (PAGE_SHIFT + 1)
259 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
260 #ifndef KMALLOC_SHIFT_LOW
261 #define KMALLOC_SHIFT_LOW       3
262 #endif
263 #endif
264 
265 #ifdef CONFIG_SLOB
266 /*
267  * SLOB passes all requests larger than one page to the page allocator.
268  * No kmalloc array is necessary since objects of different sizes can
269  * be allocated from the same page.
270  */
271 #define KMALLOC_SHIFT_HIGH      PAGE_SHIFT
272 #define KMALLOC_SHIFT_MAX       (MAX_ORDER + PAGE_SHIFT - 1)
273 #ifndef KMALLOC_SHIFT_LOW
274 #define KMALLOC_SHIFT_LOW       3
275 #endif
276 #endif
277 
278 /* Maximum allocatable size */
279 #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_MAX)
280 /* Maximum size for which we actually use a slab cache */
281 #define KMALLOC_MAX_CACHE_SIZE  (1UL << KMALLOC_SHIFT_HIGH)
282 /* Maximum order allocatable via the slab allocagtor */
283 #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
284 
285 /*
286  * Kmalloc subsystem.
287  */
288 #ifndef KMALLOC_MIN_SIZE
289 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
290 #endif
291 
292 /*
293  * This restriction comes from byte sized index implementation.
294  * Page size is normally 2^12 bytes and, in this case, if we want to use
295  * byte sized index which can represent 2^8 entries, the size of the object
296  * should be equal or greater to 2^12 / 2^8 = 2^4 = 16.
297  * If minimum size of kmalloc is less than 16, we use it as minimum object
298  * size and give up to use byte sized index.
299  */
300 #define SLAB_OBJ_MIN_SIZE      (KMALLOC_MIN_SIZE < 16 ? \
301                                (KMALLOC_MIN_SIZE) : 16)
302 
303 /*
304  * Whenever changing this, take care of that kmalloc_type() and
305  * create_kmalloc_caches() still work as intended.
306  */
307 enum kmalloc_cache_type {
308         KMALLOC_NORMAL = 0,
309         KMALLOC_RECLAIM,
310 #ifdef CONFIG_ZONE_DMA
311         KMALLOC_DMA,
312 #endif
313         NR_KMALLOC_TYPES
314 };
315 
316 #ifndef CONFIG_SLOB
317 extern struct kmem_cache *
318 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
319 
320 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
321 {
322 #ifdef CONFIG_ZONE_DMA
323         /*
324          * The most common case is KMALLOC_NORMAL, so test for it
325          * with a single branch for both flags.
326          */
327         if (likely((flags & (__GFP_DMA | __GFP_RECLAIMABLE)) == 0))
328                 return KMALLOC_NORMAL;
329 
330         /*
331          * At least one of the flags has to be set. If both are, __GFP_DMA
332          * is more important.
333          */
334         return flags & __GFP_DMA ? KMALLOC_DMA : KMALLOC_RECLAIM;
335 #else
336         return flags & __GFP_RECLAIMABLE ? KMALLOC_RECLAIM : KMALLOC_NORMAL;
337 #endif
338 }
339 
340 /*
341  * Figure out which kmalloc slab an allocation of a certain size
342  * belongs to.
343  * 0 = zero alloc
344  * 1 =  65 .. 96 bytes
345  * 2 = 129 .. 192 bytes
346  * n = 2^(n-1)+1 .. 2^n
347  */
348 static __always_inline unsigned int kmalloc_index(size_t size)
349 {
350         if (!size)
351                 return 0;
352 
353         if (size <= KMALLOC_MIN_SIZE)
354                 return KMALLOC_SHIFT_LOW;
355 
356         if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
357                 return 1;
358         if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
359                 return 2;
360         if (size <=          8) return 3;
361         if (size <=         16) return 4;
362         if (size <=         32) return 5;
363         if (size <=         64) return 6;
364         if (size <=        128) return 7;
365         if (size <=        256) return 8;
366         if (size <=        512) return 9;
367         if (size <=       1024) return 10;
368         if (size <=   2 * 1024) return 11;
369         if (size <=   4 * 1024) return 12;
370         if (size <=   8 * 1024) return 13;
371         if (size <=  16 * 1024) return 14;
372         if (size <=  32 * 1024) return 15;
373         if (size <=  64 * 1024) return 16;
374         if (size <= 128 * 1024) return 17;
375         if (size <= 256 * 1024) return 18;
376         if (size <= 512 * 1024) return 19;
377         if (size <= 1024 * 1024) return 20;
378         if (size <=  2 * 1024 * 1024) return 21;
379         if (size <=  4 * 1024 * 1024) return 22;
380         if (size <=  8 * 1024 * 1024) return 23;
381         if (size <=  16 * 1024 * 1024) return 24;
382         if (size <=  32 * 1024 * 1024) return 25;
383         if (size <=  64 * 1024 * 1024) return 26;
384         BUG();
385 
386         /* Will never be reached. Needed because the compiler may complain */
387         return -1;
388 }
389 #endif /* !CONFIG_SLOB */
390 
391 void *__kmalloc(size_t size, gfp_t flags) __assume_kmalloc_alignment __malloc;
392 void *kmem_cache_alloc(struct kmem_cache *, gfp_t flags) __assume_slab_alignment __malloc;
393 void kmem_cache_free(struct kmem_cache *, void *);
394 
395 /*
396  * Bulk allocation and freeing operations. These are accelerated in an
397  * allocator specific way to avoid taking locks repeatedly or building
398  * metadata structures unnecessarily.
399  *
400  * Note that interrupts must be enabled when calling these functions.
401  */
402 void kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
403 int kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
404 
405 /*
406  * Caller must not use kfree_bulk() on memory not originally allocated
407  * by kmalloc(), because the SLOB allocator cannot handle this.
408  */
409 static __always_inline void kfree_bulk(size_t size, void **p)
410 {
411         kmem_cache_free_bulk(NULL, size, p);
412 }
413 
414 #ifdef CONFIG_NUMA
415 void *__kmalloc_node(size_t size, gfp_t flags, int node) __assume_kmalloc_alignment __malloc;
416 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node) __assume_slab_alignment __malloc;
417 #else
418 static __always_inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
419 {
420         return __kmalloc(size, flags);
421 }
422 
423 static __always_inline void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t flags, int node)
424 {
425         return kmem_cache_alloc(s, flags);
426 }
427 #endif
428 
429 #ifdef CONFIG_TRACING
430 extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t) __assume_slab_alignment __malloc;
431 
432 #ifdef CONFIG_NUMA
433 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
434                                            gfp_t gfpflags,
435                                            int node, size_t size) __assume_slab_alignment __malloc;
436 #else
437 static __always_inline void *
438 kmem_cache_alloc_node_trace(struct kmem_cache *s,
439                               gfp_t gfpflags,
440                               int node, size_t size)
441 {
442         return kmem_cache_alloc_trace(s, gfpflags, size);
443 }
444 #endif /* CONFIG_NUMA */
445 
446 #else /* CONFIG_TRACING */
447 static __always_inline void *kmem_cache_alloc_trace(struct kmem_cache *s,
448                 gfp_t flags, size_t size)
449 {
450         void *ret = kmem_cache_alloc(s, flags);
451 
452         ret = kasan_kmalloc(s, ret, size, flags);
453         return ret;
454 }
455 
456 static __always_inline void *
457 kmem_cache_alloc_node_trace(struct kmem_cache *s,
458                               gfp_t gfpflags,
459                               int node, size_t size)
460 {
461         void *ret = kmem_cache_alloc_node(s, gfpflags, node);
462 
463         ret = kasan_kmalloc(s, ret, size, gfpflags);
464         return ret;
465 }
466 #endif /* CONFIG_TRACING */
467 
468 extern void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
469 
470 #ifdef CONFIG_TRACING
471 extern void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) __assume_page_alignment __malloc;
472 #else
473 static __always_inline void *
474 kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
475 {
476         return kmalloc_order(size, flags, order);
477 }
478 #endif
479 
480 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
481 {
482         unsigned int order = get_order(size);
483         return kmalloc_order_trace(size, flags, order);
484 }
485 
486 /**
487  * kmalloc - allocate memory
488  * @size: how many bytes of memory are required.
489  * @flags: the type of memory to allocate.
490  *
491  * kmalloc is the normal method of allocating memory
492  * for objects smaller than page size in the kernel.
493  *
494  * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN
495  * bytes. For @size of power of two bytes, the alignment is also guaranteed
496  * to be at least to the size.
497  *
498  * The @flags argument may be one of the GFP flags defined at
499  * include/linux/gfp.h and described at
500  * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>`
501  *
502  * The recommended usage of the @flags is described at
503  * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>`
504  *
505  * Below is a brief outline of the most useful GFP flags
506  *
507  * %GFP_KERNEL
508  *      Allocate normal kernel ram. May sleep.
509  *
510  * %GFP_NOWAIT
511  *      Allocation will not sleep.
512  *
513  * %GFP_ATOMIC
514  *      Allocation will not sleep.  May use emergency pools.
515  *
516  * %GFP_HIGHUSER
517  *      Allocate memory from high memory on behalf of user.
518  *
519  * Also it is possible to set different flags by OR'ing
520  * in one or more of the following additional @flags:
521  *
522  * %__GFP_HIGH
523  *      This allocation has high priority and may use emergency pools.
524  *
525  * %__GFP_NOFAIL
526  *      Indicate that this allocation is in no way allowed to fail
527  *      (think twice before using).
528  *
529  * %__GFP_NORETRY
530  *      If memory is not immediately available,
531  *      then give up at once.
532  *
533  * %__GFP_NOWARN
534  *      If allocation fails, don't issue any warnings.
535  *
536  * %__GFP_RETRY_MAYFAIL
537  *      Try really hard to succeed the allocation but fail
538  *      eventually.
539  */
540 static __always_inline void *kmalloc(size_t size, gfp_t flags)
541 {
542         if (__builtin_constant_p(size)) {
543 #ifndef CONFIG_SLOB
544                 unsigned int index;
545 #endif
546                 if (size > KMALLOC_MAX_CACHE_SIZE)
547                         return kmalloc_large(size, flags);
548 #ifndef CONFIG_SLOB
549                 index = kmalloc_index(size);
550 
551                 if (!index)
552                         return ZERO_SIZE_PTR;
553 
554                 return kmem_cache_alloc_trace(
555                                 kmalloc_caches[kmalloc_type(flags)][index],
556                                 flags, size);
557 #endif
558         }
559         return __kmalloc(size, flags);
560 }
561 
562 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
563 {
564 #ifndef CONFIG_SLOB
565         if (__builtin_constant_p(size) &&
566                 size <= KMALLOC_MAX_CACHE_SIZE) {
567                 unsigned int i = kmalloc_index(size);
568 
569                 if (!i)
570                         return ZERO_SIZE_PTR;
571 
572                 return kmem_cache_alloc_node_trace(
573                                 kmalloc_caches[kmalloc_type(flags)][i],
574                                                 flags, node, size);
575         }
576 #endif
577         return __kmalloc_node(size, flags, node);
578 }
579 
580 /**
581  * kmalloc_array - allocate memory for an array.
582  * @n: number of elements.
583  * @size: element size.
584  * @flags: the type of memory to allocate (see kmalloc).
585  */
586 static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
587 {
588         size_t bytes;
589 
590         if (unlikely(check_mul_overflow(n, size, &bytes)))
591                 return NULL;
592         if (__builtin_constant_p(n) && __builtin_constant_p(size))
593                 return kmalloc(bytes, flags);
594         return __kmalloc(bytes, flags);
595 }
596 
597 /**
598  * kcalloc - allocate memory for an array. The memory is set to zero.
599  * @n: number of elements.
600  * @size: element size.
601  * @flags: the type of memory to allocate (see kmalloc).
602  */
603 static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
604 {
605         return kmalloc_array(n, size, flags | __GFP_ZERO);
606 }
607 
608 /*
609  * kmalloc_track_caller is a special version of kmalloc that records the
610  * calling function of the routine calling it for slab leak tracking instead
611  * of just the calling function (confusing, eh?).
612  * It's useful when the call to kmalloc comes from a widely-used standard
613  * allocator where we care about the real place the memory allocation
614  * request comes from.
615  */
616 extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
617 #define kmalloc_track_caller(size, flags) \
618         __kmalloc_track_caller(size, flags, _RET_IP_)
619 
620 static inline void *kmalloc_array_node(size_t n, size_t size, gfp_t flags,
621                                        int node)
622 {
623         size_t bytes;
624 
625         if (unlikely(check_mul_overflow(n, size, &bytes)))
626                 return NULL;
627         if (__builtin_constant_p(n) && __builtin_constant_p(size))
628                 return kmalloc_node(bytes, flags, node);
629         return __kmalloc_node(bytes, flags, node);
630 }
631 
632 static inline void *kcalloc_node(size_t n, size_t size, gfp_t flags, int node)
633 {
634         return kmalloc_array_node(n, size, flags | __GFP_ZERO, node);
635 }
636 
637 
638 #ifdef CONFIG_NUMA
639 extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
640 #define kmalloc_node_track_caller(size, flags, node) \
641         __kmalloc_node_track_caller(size, flags, node, \
642                         _RET_IP_)
643 
644 #else /* CONFIG_NUMA */
645 
646 #define kmalloc_node_track_caller(size, flags, node) \
647         kmalloc_track_caller(size, flags)
648 
649 #endif /* CONFIG_NUMA */
650 
651 /*
652  * Shortcuts
653  */
654 static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
655 {
656         return kmem_cache_alloc(k, flags | __GFP_ZERO);
657 }
658 
659 /**
660  * kzalloc - allocate memory. The memory is set to zero.
661  * @size: how many bytes of memory are required.
662  * @flags: the type of memory to allocate (see kmalloc).
663  */
664 static inline void *kzalloc(size_t size, gfp_t flags)
665 {
666         return kmalloc(size, flags | __GFP_ZERO);
667 }
668 
669 /**
670  * kzalloc_node - allocate zeroed memory from a particular memory node.
671  * @size: how many bytes of memory are required.
672  * @flags: the type of memory to allocate (see kmalloc).
673  * @node: memory node from which to allocate
674  */
675 static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
676 {
677         return kmalloc_node(size, flags | __GFP_ZERO, node);
678 }
679 
680 unsigned int kmem_cache_size(struct kmem_cache *s);
681 void __init kmem_cache_init_late(void);
682 
683 #if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
684 int slab_prepare_cpu(unsigned int cpu);
685 int slab_dead_cpu(unsigned int cpu);
686 #else
687 #define slab_prepare_cpu        NULL
688 #define slab_dead_cpu           NULL
689 #endif
690 
691 #endif  /* _LINUX_SLAB_H */
692 

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